This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A081220 #16 Aug 09 2025 17:23:22 %S A081220 5,101,181,313,353,373,757,797,929,10301,10501,10601,12421,12721, %T A081220 12821,14341,14741,16061,16361,16561,16661,18181,18481,31013,31513, %U A081220 33533,35053,35153,35353,35753,37273,37573,39293,71317,71917,73037,73237,73637,75557,77377 %N A081220 Palindromic primes = 1 mod 4. %C A081220 Intersection of A002385 and A002144. %H A081220 Harvey P. Dale, <a href="/A081220/b081220.txt">Table of n, a(n) for n = 1..1500</a> %t A081220 Select[Select[Prime[Range[10000]], # == FromDigits[Reverse[IntegerDigits[ # ]]] &], Mod[ #, 4] == 1 &] (* _Harvey P. Dale_, Oct 15 2006 *) %t A081220 Select[Prime[Range[7500]],#==IntegerReverse[#]&&Mod[#,4]==1&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Oct 18 2016 *) %Y A081220 Cf. A002385, A002144. %K A081220 nonn,base %O A081220 1,1 %A A081220 _Lekraj Beedassy_, Apr 18 2003, corrected Sep 28 2006 %E A081220 Corrected by _Harvey P. Dale_, Oct 15 2006